It is well known in the newspaper industry to employ inserting machines (i.e., stuffers) for the purpose of automatically introducing inserts into a signature. This technique is extremely advantageous in the publishing of Sunday newspapers. Many of the magazine inserts for the upcoming Sunday edition are printed well ahead of time, but cannot be inserted into the signature until the news part of the newspaper is printed.
In newspaper plants, it is typical to count the signatures in order to form signature bundles to determine accurate counts for proper control over delivery and distribution of the signatures.
The problem of accurately counting the stream of signatures leaving an insert machine is a difficult one due to the thickness of the signatures and the poor "nose" of the signature caused by the inserted products contained within the signature jacket.
The signature being delivered from a press has a distinct and well-defined nose (leading edge), which is used to great advantage for accurately sensing each signature, either through the use of a non-contact optical sensor or a more conventional electromechanical cog wheel type sensor.
Distinct signature nose almost never exists in signatures having inserts. The leading edge of a signature, frequently referred to as the nose, quite often has several humps caused by the plurality of inserted sections protruding through the skin of the jacket. These humps cause conventional counters to miscount.
Another problem which occurs with inserted products is the signature jacket is often at times missing due to misfeeds occurring in the insert machine. As a result, several of the insert sections of the newspapapers are spread out slightly and a conventional count sensor may erroneously pick up every insert section, or at least some of them, resulting in miscounts.